The present invention relates to an image forming apparatus, and more particularly to an image forming apparatus capable of reducing a frequency of exchanging a toner container by efficiently using a dead space for a large capacity toner storage. The present invention also relates to a method of manufacturing the above-mentioned image forming apparatus.
Conventionally, an electrophotographic image forming apparatus uses a development mechanism which develops an electrostatic latent image formed on an image carrying member into a visual image. In particular, an electrophotographic image forming apparatus using a two-component developer for the development mechanism adopts a specific structure in which a toner storage such as a toner bottle, a toner cartridge, a toner tank, and the like is arranged close to the development mechanism and toner is transported with a transportation mechanism such as an auger.
In addition, an electrophotographic image forming apparatus provided with color capability is known to employ four development mechanisms with four toner storages for colors of yellow, magenta, cyan, and black.
It is a general requirement for such an image forming apparatus to have a compact size without sacrificing a capacity of the toner storage. However, the toner storage is needed to be arranged close to the development mechanism in an engine of the image forming apparatus and therefore the miniaturization of the engine is not freely carried out and is limited to a certain level. Accordingly, flexibility of a machine design itself is constrained.
Japanese Laid-Open Patent Application Publication, No. 2001-305843, describes an image forming apparatus which has a toner storage arranged in a separate unit from a development mechanism since the toner contained in the toner storage is transported to the development mechanism with a screw pump called a mohno-pump.
However, as a recent trend, the image forming apparatus has been reduced in size, and consequently decreases an amount of dead space left therein which can be used to install the separate unit of the toner storage. Conversely, the toner capacity required to be as great as possible because an exchange of the toner storage is preferably performed as infrequently as possible. Further, in a case of a color image forming apparatus, the capacity of a black color toner is generally required to be greater than other colors because the black color toner is consumed to a greater degree than other toners.
In view of the foregoing, it is an object of the present invention to provide a novel image forming apparatus which can store a large capacity of toner without sacrificing the reduction in size of the print engine.
Another object of the present invention is to provide a novel image forming method which can store a large capacity of toner without sacrificing the reduction in size of the print engine.
To achieve the above-mentioned object, in one example, a novel image forming apparatus includes a plural sets of image forming mechanisms and an intermediate transfer member. Each of the plural sets of image forming mechanisms includes an image carrying member, a development mechanism, and a toner storage. The image carrying member is configured to carry an electrostatic latent image thereon. The development mechanism is configured to develop the electrostatic latent image formed on the image carrying member into a visual image. The toner storage is detachably installed in the apparatus and is configured to store toner therein. The intermediate transfer member is configured to sequentially receive toner images formed by the plurality of image forming mechanisms into a composite toner image and to transfer the composite toner image to a recording sheet. In this apparatus, a plurality of the toner storages have an approximately rectangular shape having a rectangular transverse section. Further, at least one of the plurality of the toner storages has a greater toner capacity than others of the plurality of the toner storages, and a length of a short side of the rectangular transverse section of the at least one of the plurality of the toner storages having the greater toner capacity is approximately equal to lengths of long sides of the rectangular transverse sections of the others of the plurality of the toner storages.
The plurality of the toner storages may be aligned such that the short side of the rectangular transverse section of the at least one of the plurality of the toner storages and the long sides of the rectangular transverse sections of the others of the plurality of the toner storages are arranged parallel to each other.
Each of the plurality of the image forming mechanisms may further include a toner replenishing mechanism including a screw pump transporting with a negative pressure the toner from the corresponding toner storage to the corresponding development mechanism. In this case, each of the at least one of the plurality of the toner storages having the greater toner capacity is provided with a single air pump discharging a jet air to an inside of the corresponding toner storage and the others of the plurality of the toner storages are provided with a common air pump discharging a jet air to an inside of the toner storages.
The toner storage included in the at least one of the plurality of the toner storages having the greater toner capacity may be divided into a plurality of toner containers.
The plurality of toner containers divided from the toner storage and the others of the plurality of the toner storages may have a substantially common size and an approximately rectangular shape having a rectangular transverse section.
Further, to achieve the above-mentioned object, in one example, a novel method of making an image forming apparatus includes the steps of providing and placing. The providing step provides a plural sets of image forming mechanisms. Each of the plural sets of image forming mechanisms includes an image carrying member, a development mechanism, and a toner storage. The image carrying member is configured to carry an electrostatic latent image thereon. The development mechanism is configured to develop the electrostatic latent image formed on the image carrying member into a visual image. The toner storage is detachably installed in the apparatus and is configured to store toner therein. The placing step places an intermediate transfer member configured to sequentially receive toner images formed by the plurality of image forming mechanisms into a composite toner image and to transfer the composite toner image to a recording sheet. In this method, a plurality of the toner storages have an approximately rectangular shape having a rectangular transverse section. Further, at least one of the plurality of the toner storages has a greater toner capacity than others of the plurality of the toner storages, and a length of a short side of the rectangular transverse section of the at least one of the plurality of the toner storages having the greater toner capacity is approximately equal to lengths of long sides of the rectangular transverse sections of the others of the plurality of the toner storages.
The plurality of the toner storages may be aligned such that the short side of the rectangular transverse section of the at least one of the plurality of the toner storages and the long sides of the rectangular transverse sections of the others of the plurality of the toner storages are arranged parallel to each other.
Each of the plurality of the image forming mechanisms may further include a toner replenishing mechanism including a screw pump transporting with a negative pressure the toner from the corresponding toner storage to the corresponding development mechanism. In this case, each of the at least one of the plurality of the toner storages having the greater toner capacity is provided with a single air pump discharging a jet air to an inside of the corresponding toner storage and the others of the plurality of the toner storages are provided with a common air pump discharging a jet air to an inside of the toner storages.
The toner storage included in the at least one of the plurality of the toner storages having the greater toner capacity may be divided into a plurality of toner containers.
The plurality of toner containers divided from the toner storage and the others of the plurality of the toner storages may have a substantially common size and an approximately rectangular shape having a rectangular transverse section.